
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

#include "eloop.h"


struct eloop_sock
{
    int sock;
    void *eloop_data;
    void *user_data;
    void (*handler)(int sock, void *eloop_ctx, void *sock_ctx);
};

struct eloop_timeout
{
    struct timeval time;
    void *eloop_data;
    void *user_data;
    void (*handler)(void *eloop_ctx, void *sock_ctx);
    struct eloop_timeout *next;
};

struct eloop_signal
{
    int sig;
    void *user_data;
    void (*handler)(int sig, void *eloop_ctx, void *signal_ctx);
};

struct eloop_data
{
    void *user_data;

    int max_sock, reader_count;
    struct eloop_sock *readers;

    struct eloop_timeout *timeout;

    int signal_count;
    struct eloop_signal *signals;

    int terminate;
    int reload;
};

static struct eloop_data eloop;


void eloop_init(void *user_data)
{
    memset(&eloop, 0, sizeof(eloop));
    eloop.user_data = user_data;
}


int eloop_register_read_sock(int sock, void (*handler)(int sock, void *eloop_ctx, void *sock_ctx),
                             void *eloop_data, void *user_data)
{
    struct eloop_sock *tmp;

    tmp = (struct eloop_sock *) realloc(eloop.readers, (eloop.reader_count + 1) * sizeof(struct eloop_sock));
    if (tmp == NULL)
        return -1;

    tmp[eloop.reader_count].sock = sock;
    tmp[eloop.reader_count].eloop_data = eloop_data;
    tmp[eloop.reader_count].user_data = user_data;
    tmp[eloop.reader_count].handler = handler;
    eloop.reader_count++;
    eloop.readers = tmp;

    if (sock > eloop.max_sock)
        eloop.max_sock = sock;

    return 0;
}

int eloop_register_timeout(unsigned int secs, unsigned int usecs,
                           void (*handler)(void *eloop_ctx, void *timeout_ctx),
                           void *eloop_data, void *user_data)
{
    struct eloop_timeout *timeout, *tmp, *prev;

    timeout = (struct eloop_timeout *) malloc(sizeof(*timeout));
    if (timeout == NULL)
        return -1;

    gettimeofday(&timeout->time, NULL);
    timeout->time.tv_sec += secs;
    timeout->time.tv_usec += usecs;

    while (timeout->time.tv_usec >= 1000000)
    {
        timeout->time.tv_sec++;
        timeout->time.tv_usec -= 1000000;
    }
    timeout->eloop_data = eloop_data;
    timeout->user_data = user_data;
    timeout->handler = handler;
    timeout->next = NULL;

    if (eloop.timeout == NULL)
    {
        eloop.timeout = timeout;
        return 0;
    }

    prev = NULL;
    tmp = eloop.timeout;
    while (tmp != NULL)
    {
        if (timercmp(&timeout->time, &tmp->time, <))
            break;
        prev = tmp;
        tmp = tmp->next;
    }

    if (prev == NULL)
    {
        timeout->next = eloop.timeout;
        eloop.timeout = timeout;
    }
    else
    {
        timeout->next = prev->next;
        prev->next = timeout;
    }

    return 0;
}

int eloop_cancel_timeout(void (*handler)(void *eloop_ctx, void *sock_ctx),
                         void *eloop_data, void *user_data)
{
    struct eloop_timeout *timeout, *prev, *next;
    int removed = 0;

    prev = NULL;
    timeout = eloop.timeout;
    while (timeout != NULL)
    {
        next = timeout->next;

        if (timeout->handler == handler && (timeout->eloop_data == eloop_data || eloop_data == ELOOP_ALL_CTX)
            && (timeout->user_data == user_data || user_data == ELOOP_ALL_CTX))
        {
            if (prev == NULL)
                eloop.timeout = next;
            else
                prev->next = next;
            free(timeout);
            removed++;
        }
        else
            prev = timeout;

        timeout = next;
    }

    return removed;
}

static void eloop_handle_signal(int sig)
{
    int i;
    for (i = 0; i < eloop.signal_count; i++)
    {
        if (eloop.signals[i].sig == sig)
        {
            eloop.signals[i].handler(eloop.signals[i].sig, eloop.user_data, eloop.signals[i].user_data);
            break;
        }
    }
}

int eloop_register_signal(int sig, void (*handler)(int sig, void *eloop_ctx, void *signal_ctx), void *user_data)
{
    struct eloop_signal *tmp;

    tmp = (struct eloop_signal *) realloc(eloop.signals, (eloop.signal_count + 1) * sizeof(struct eloop_signal));
    if (tmp == NULL)
        return -1;

    tmp[eloop.signal_count].sig = sig;
    tmp[eloop.signal_count].user_data = user_data;
    tmp[eloop.signal_count].handler = handler;
    eloop.signal_count++;
    eloop.signals = tmp;
    signal(sig, eloop_handle_signal);

    return 0;
}

void eloop_run(void)
{
    fd_set rfds;
    int i, res;
    struct timeval tv, now;

    while (!eloop.terminate && (eloop.timeout || eloop.reader_count > 0))
    {
        if (eloop.timeout)
        {
            gettimeofday(&now, NULL);
            if (timercmp(&now, &eloop.timeout->time, >=))
                tv.tv_sec = tv.tv_usec = 0;
            else
                timersub(&eloop.timeout->time, &now, &tv);
        }

        FD_ZERO(&rfds);
        for (i = 0; i < eloop.reader_count; i++)
            FD_SET(eloop.readers[i].sock, &rfds);
        res = select(eloop.max_sock + 1, &rfds, NULL, NULL,
                     eloop.timeout ? &tv : NULL);
        if (res < 0 && errno != EINTR)
        {
            perror("select");
            return ;
        }

        /* check if some registered timeouts have occurred */
        if (eloop.timeout)
        {
            struct eloop_timeout *tmp;

            gettimeofday(&now, NULL);
            if (timercmp(&now, &eloop.timeout->time, >=))
            {
                tmp = eloop.timeout;
                eloop.timeout = eloop.timeout->next;
                tmp->handler(tmp->eloop_data, tmp->user_data);
                free(tmp);
            }

        }

        if (res <= 0)
            continue;

        for (i = 0; i < eloop.reader_count; i++)
        {
            if (FD_ISSET(eloop.readers[i].sock, &rfds))
            {
                eloop.readers[i].handler(eloop.readers[i].sock, eloop.readers[i].eloop_data, eloop.readers[i].user_data);
            }
        }
    }
}

void eloop_terminate(void)
{
    eloop.terminate = 1;
}

void eloop_reload(void)
{
    eloop.reload = 1;
}

void eloop_destroy(void)
{
    struct eloop_timeout *timeout, *prev;

    timeout = eloop.timeout;
    while (timeout != NULL)
    {
        prev = timeout;
        timeout = timeout->next;
        free(prev);
    }
    free(eloop.readers);
    free(eloop.signals);
}

int eloop_terminated(void)
{
    return eloop.terminate;
}
